It is well known to provide a medicament dispenser device in which a fluid medicament formulation is dispensed as a spray via a nozzle to the nasal cavity of a user. In general, the fluid is delivered to the nozzle upon the application of user force to a fluid pumping mechanism. Such nasal dispensers may be arranged to dispense a single dose or may alternatively be arranged with a fluid reservoir from which individual metered doses may be pumped. A general example of such a pump action nasal inhaler device is shown and described in U.S. Pat. No. 4,946,069.
It is a problem with such pump action nasal spray devices that the characteristics of the spray are to an extent dependent upon the manner of actuation by the user. If the user actuates the device in a slow or lethargic manner then the dispensing of the fluid may be less spray-like than required for effective delivery to the nasal cavity. If the rate of discharge is too low full atomisation may not occur and the spray undesirably comprises of relatively large droplets of fluid. In extreme cases, no spray is produced and the fluid simply dribbles out from the tip of the nozzle.
To improve spray characteristics, it is known to be advantageous to provide a feature to the nozzle which causes acceleration and swirling of the fluid prior to its dispensing from the nozzle as a spray. Conventionally, the inner part of the nozzle provides a housing that defines an acceleration chamber and a separate shaped insert is provided to the chamber. The insert is shaped to cause the fluid to spin or swirl prior to it being dispensed from the tip and generally takes the form of a multi-bladed propeller-shaped swirl insert.
The Applicant has appreciated that the use of a separate swirl insert can give rise to certain manufacturing challenges. In particular, the performance of the swirl insert depends to an extent upon the accuracy of its fitting within the acceleration chamber. Variation in manufacturing tolerances in the shape and sizing of both the housing defining the acceleration chamber and the swirl insert can affect swirl performance as can variation in the fitting/location of the swirl insert within the chamber. Potential issues relating to manufacturing tolerances are only exacerbated by the small size of the swirl insert, which is typically sized to have a diameter of 2-3 millimeters. The Applicant has therefore realized the desirability of forming the housing and swirl insert as a composite part.
The Applicant has however, further appreciated that different challenges exist in forming the acceleration chamber and swirl insert as a single composite part. For mass production, moulding is the preferred manufacturing process, but the complex shaping of the inner (swirl) features of such a single composite part preclude the use of moulding as a manufacturing method. In essence, the problem is that it is impossible (or at least exceptionally difficult) to create a suitable mass production tool for moulding a single part that has the required inner acceleration/swirl features.
As a solution, the Applicant has therefore devised a composite part that may impart acceleration and swirl characteristics to a fluid wherein the composite part is defined by a mating assembly of like component parts. In particular, the composite part may be formed from two like mating halves or alternatively, from three like mating thirds, wherein each component part is shaped with both acceleration and swirl creating features. Preferably, the overall composite part defines an essentially cylindrical form such that each mating half of the two-part form defines a 180° segment of the cylinder or alternatively, each mating third of the three-part form defines a 120° segment of the cylinder.
It is an object of this invention to provide a nozzle for use in a fluid dispensing device that provides effective spraying from the nozzle.
It is a further object of this invention to provide a nozzle for use in a fluid dispensing device that on manufacture does not require the bringing together of separate acceleration chamber housing and swirl insert parts.
Applicant's co-pending PCT Patent Application No. WO 2004/094068 describes a nasal dispensing nozzle comprising a body defining a fluid flow channel; an inlet port defining an inlet to said channel, the inlet port shaped for receipt of said discharge outlet to enable delivery of said pumped fluid medicament to the channel; and an outlet port defining an outlet from said channel, the outlet port shaped for insertion into the nasal cavity of a user to enable delivery of the pumped fluid medicament thereto. A screw thread path is provided to the channel between the inlet and said outlet to impart angular momentum to the pumped fluid medicament.